Spring Batch not deserialising dates - spring

Question

I'm adding an object in the JobExecution context of spring batch, which contains an Instant field.
It's getting serialised as follows:
{
"startFrom": {
"nano": 0,
"epochSecond": 1541116800
}
}
However, Spring Batch doesn't seem to be able to deserialise it.
Caused by: java.lang.IllegalArgumentException: Unable to deserialize the execution context
at org.springframework.batch.core.repository.dao.JdbcExecutionContextDao$ExecutionContextRowMapper.mapRow(JdbcExecutionContextDao.java:325)
at org.springframework.batch.core.repository.dao.JdbcExecutionContextDao$ExecutionContextRowMapper.mapRow(JdbcExecutionContextDao.java:309)
at org.springframework.jdbc.core.RowMapperResultSetExtractor.extractData(RowMapperResultSetExtractor.java:93)
at org.springframework.jdbc.core.RowMapperResultSetExtractor.extractData(RowMapperResultSetExtractor.java:60)
at org.springframework.jdbc.core.JdbcTemplate$1.doInPreparedStatement(JdbcTemplate.java:667)
at org.springframework.jdbc.core.JdbcTemplate.execute(JdbcTemplate.java:605)
at org.springframework.jdbc.core.JdbcTemplate.query(JdbcTemplate.java:657)
at org.springframework.jdbc.core.JdbcTemplate.query(JdbcTemplate.java:688)
at org.springframework.jdbc.core.JdbcTemplate.query(JdbcTemplate.java:700)
at org.springframework.jdbc.core.JdbcTemplate.query(JdbcTemplate.java:756)
at org.springframework.batch.core.repository.dao.JdbcExecutionContextDao.getExecutionContext(JdbcExecutionContextDao.java:112)
at org.springframework.batch.core.explore.support.SimpleJobExplorer.getJobExecutionDependencies(SimpleJobExplorer.java:202)
at org.springframework.batch.core.explore.support.SimpleJobExplorer.getJobExecutions(SimpleJobExplorer.java:83)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.base/java.lang.reflect.Method.invoke(Method.java:564)
at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:343)
at org.springframework.aop.framework.ReflectiveMethod
When doing some research I see that Jackson has a JavaTimeModule to serialise/deserialise Instant and other date classes.
However, in the Jackson2ExecutionContextStringSerializer class, it creates the ObjectMapper as follows, not registering the right module:
public Jackson2ExecutionContextStringSerializer() {
this.objectMapper = new ObjectMapper();
this.objectMapper.configure(MapperFeature.DEFAULT_VIEW_INCLUSION, false);
this.objectMapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, true);
this.objectMapper.enableDefaultTyping();
this.objectMapper.registerModule(new JobParametersModule());
}
Is there a reason for Spring Batch not to use the autowired ObjectMapper? Or a reason for them not to register the JavaTimeModule?
Is there maybe a workaround this issue?
Thanks!
Edit:
I've found how to overwrite this object mapper:
#Bean
public JobRepository createJobRepository() throws Exception {
ObjectMapper objectMapper = new ObjectMapper().registerModule(new JavaTimeModule()).findAndRegisterModules();
Jackson2ExecutionContextStringSerializer defaultSerializer = new Jackson2ExecutionContextStringSerializer();
defaultSerializer.setObjectMapper(objectMapper);
JobRepositoryFactoryBean factory = new JobRepositoryFactoryBean();
factory.setDataSource(dataSource);
factory.setTransactionManager(transactionManager);
factory.setSerializer(defaultSerializer);
factory.afterPropertiesSet();
return factory.getObject();
}
However, even with this, the issue persists.

Answer 1

The following worked for me. I am extending Mahmoud Ben Hassine's answer above which didn't work for Nicolas Widart. (I don't have enough reputation to just comment).
#Bean
public BatchConfigurer configurer(DataSource dataSource, PlatformTransactionManager transactionManager,
ObjectMapper objectMapper) {
return new DefaultBatchConfigurer(dataSource) {
final Jackson2ExecutionContextStringSerializer serializer = new Jackson2ExecutionContextStringSerializer();
#Override
protected JobRepository createJobRepository() throws Exception {
serializer.setObjectMapper(objectMapper);
JobRepositoryFactoryBean factory = new JobRepositoryFactoryBean();
factory.setDataSource(dataSource);
factory.setTransactionManager(transactionManager);
factory.setSerializer(serializer);
factory.afterPropertiesSet();
return factory.getObject();
}
#Override
protected JobExplorer createJobExplorer() throws Exception {
serializer.setObjectMapper(objectMapper);
JobExplorerFactoryBean jobExplorerFactoryBean = new JobExplorerFactoryBean();
jobExplorerFactoryBean.setSerializer(serializer);
jobExplorerFactoryBean.setDataSource(dataSource);
jobExplorerFactoryBean.afterPropertiesSet();
return jobExplorerFactoryBean.getObject();
}
};
}
(I have defined an ObjectMapper bean in another #Configuration class.) The important thing here is to also override the createJobExplorer() method and set the correct ExecutionContextSerializer there, as this method will call getTarget() on the JobExplorerFactoryBean, which will set a vanilla ExecutionContextSerializer if there is none set and which causes the error you described.

Answer 2

The code you showed is the default initialization of the serializer. You can override it by providing a custom object mapper that you pre-configure with the modules you need. Here is an example:
#Bean
public JobRepository jobRepository() throws Exception {
ObjectMapper objectMapper = null; // configure the object mapper as required
Jackson2ExecutionContextStringSerializer serializer = new Jackson2ExecutionContextStringSerializer();
serializer.setObjectMapper(objectMapper);
JobRepositoryFactoryBean jobRepositoryFactoryBean = new JobRepositoryFactoryBean();
jobRepositoryFactoryBean.setSerializer(serializer);
// set other properties on the jobRepositoryFactoryBean
jobRepositoryFactoryBean.afterPropertiesSet();
return jobRepositoryFactoryBean.getObject();
}
Hope this helps.

Answer 3

UPDATE
Spring batch now has a fix that allows you to customise your ObjectMapper while also getting all of the default setup that Jackson2ExecutionContextStringSerialier does internally after this issue was addressed: https://jira.spring.io/browse/BATCH-2828.
The fix is in 4.2.0 which at time of writing is currently at RC1.
Original answer
I've noticed similar problems. I need to customise ObjectMapper to add KotlinModule for dealing with kotlin data classes. Unfortunately, the way Jackson2ExecutionContextStringSerializer is currently written is not very extensible. As you have seen from the default ObjectMapper that was created there are some defaults that were added, including a fix for deserialisation issues with job parameters: https://jira.spring.io/browse/BATCH-2680.
The JobParametersModule they setup is a private class and as such we cannot setup ObjectMapper with the same features and add to it.
I have raised an issue for this in Jira: https://jira.spring.io/browse/BATCH-2828
The dirty workaround until this is fixed is to copy and paste the source code for JobParmetersModule so you can register the same in your override.